Method of double-sided printing of a laminate and product obtained thereby

ABSTRACT

A method of double-sided printing, in effect, on opposite or both surfaces of a layer on a multi-layered foil laminate. Moreover, also disclosed is the provision of a novel multi-layered foil laminate having at least one layer, preferably an exterior layer which is constituted of a plastic film material, and which is provided with printing on both surfaces of the layer. In essence, the inventive method of double-sided printing includes initially printing on a first side of an outer layer of a plastic film material, preferably such as polyester, wherein the printing is imparted to the side or surface of the plastic film material facing towards an underlying metallic foil to which it is to be adhered. Thereafter, in order to effectuate the printing on the opposite or external surface of the outer plastic film material, the laminated foil has thermal transfer printing imparted to the outer surface of the plastic film layer, preferably through the intermediary of a ceramic printing head, imparting further indicia indicative of specific information relative to the contents of a package which is to be equipped with the foil laminate.

This is a divisional of copending application Ser. No. 08/106,386, filedon Aug. 13, 1993.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a method of double-sided printing, ineffect, on opposite or both surfaces of a layer on a multi-layered foillaminate. Moreover, the invention is also directed to the provision of anovel multi-layered foil laminate having at least one layer, preferablyan exterior layer which is constituted of a plastic film material, andwhich is provided with printing on both surfaces of the layer.

The utilization of foil laminates which possess an external surfacewhich is imprinted with various legends and indicia, and whereby thefoil laminate may be utilized, among numerous other physicalapplications, as lid stock for plastic packages, such as the so-called"blister packages" of the injection molded type, is well-known in thepackaging technology.

2. Discussion of the Prior Art

In many instances, the externally arranged layer of the lid orcover-forming foil laminate; in essence, the layer having a surfacefacing the outside of the package, may be provided with suitableprinting. For example, such printing may consist of indicia or legendsidentifying the manufacturer, the manufacturer's logo and miscellaneousinformation and decorative and advertising indicia identifying theproduct in the package, and include suitable variable technicalinformation, such as expiration dates, lot numbers and other dataspecific to the packaged product.

Basically, such multi-layered foil laminates in the form of webs whichare employed for lid stock purposes include outer layers of suitableplastic film material adhesively fastened to both sides or oppositesurfaces of a foil web. Such a foil web is ordinarily constituted of asuitable metallic material, which may be aluminum or the like, andwherein one of the plastic film material layers is adapted to beadhesively secured, such as by means of heat scaling or the like, to theinjection- molded material of the plastic container or package whosecontents it is adapted to seal therein. Frequently, blister packages orsimilar plastic containers which have covers in the shape of foillaminates applied thereto are subjected to potentially damagingtemperature and/or environmental conditions. This may be the case whenthe entire package is subjected to sterilization, as in the instancewhen the product housed therein is intended to be employed in a medicalcapacity; for example, a product such as a contact lens which is adaptedto be packed in a sterile saline solution and sealed in a compartment orcavity of the package.

It is essential to be able to ensure that the printing which is normallyprovided on the exterior of the package will safely withstand theseabove-mentioned conditions without either being completely obliteratedor even only rendered partially illegible. Consequently, it is animportant aspect that suitable kinds of printing be employed which willnot only remain stable under such adverse physical conditions, but whichwill also avoid any deleterious effects to be imparted thereto. Thus,for instance, when the outer plastic film material layer at one side ofthe laminate is constituted so as to possess a printable and generallytransparent nature; for instance, such as a polyester film. Currentlyemployed types of printing are not sufficiently adequate to meet thestringent demands of industry. Thus, the utilization of laser printingdoes not always provide for a satisfactory printing result, while hotstamp printing produces impressions in the laminate which may adverselyaffect the mechanical sealing properties thereof with regard to theunderlying surface portions of the package or container to which thelaminate is to be heat sealed or bonded.

SUMMARY OF THE INVENTION

Accordingly, the present invention provides for a novel and inventivemethod of implementing so-called double-sided printing or, in effect,printing on both surfaces of an outer layer of a foil laminate. Inessence, the inventive method of double-sided printing includesinitially printing on a first side of an outer layer of a plastic filmmaterial, preferably such as polyester, wherein the printing is impartedto the side or surface of the plastic film material facing towards anunderlying metallic foil to which it is to be adhered, and wherein theprinting is applied to the plastic film material through theintermediary of either reverse or other suitable halftone colorprinting. Subsequent to this printing on the one side of the outerplastic film layer having been completed, the plastic film material isadhesively secured or bonded at the printed surface thereof to theunderlying metallic foil, such as through the interposition of asuitable adhesive.

Thereafter, in order to effectuate the printing on the opposite orexternal surface of the outer plastic film material, the web of thepreviously laminated foil structure is adapted to be advanced to asuitable printing arrangement. This printing arrangement causes thermaltransfer printing to be applied to the exterior surface of this outerplastic film layer of the laminate at predetermined locales, preferablythrough the intermediary of a ceramic printing head, printing furtherindicia which are specifically indicative of information relative to theparticular contents of a package which is to be equipped with the foillaminate. The method of application of the printing provides for anefficient mode of imprinting in a double-sided manner both surfaces ofthe outer plastic film material, the latter of which may be preferablyconstituted from but not limited to polyester, the properties of whichare well suited to thermal transfer printing in view of the porousnature of polyester. This type of thermal transfer printing will notform any impressions in the foil laminate while being adapted towithstand high temperatures and other adverse environmental conditionsfor considerable periods of time without any deteriorating effects beingencountered by the printing on the outside of the laminate.

The foil laminate, which is initially provided as a continuous sheet orweb from a suitable supply roll or the like, may also have the oppositesurfaces of the metallic foil provided with a suitable adhesive so as toadhesively contact and be bonded to a further plastic film material,with such film material being preferably constituted from apolypropylene. The latter, in turn, is adapted to be bonded tocontiguous sealing surfaces on an injection-molded shaped plasticcontainer or package, which may be constituted of polypropylene, such asby means of heat sealing or the like, so as to form a complete packagingstructure as is well known in the packaging technology. A "blisterpackage" of this type is disclosed, for example, in U.S. Pat. No.4,691,820, commonly assigned to the assignee of this application.

In order to facilitate the accurate and precisely located printing onthe outer surface of the plastic film material through the intermediaryof the thermal transfer printing, means are provided to enable a preciseregistry with the underlying printing on the opposite surface of theplastic film material. The printing which is provided on the inwardlyfacing or opposite surface of the first-mentioned plastic film material,and which is located within the laminate adhered to the foil web mayincorporate suitable print fields which formulate guides for printingregistration upon being scanned by a suitable optical sensor locatedproximate the exterior of the foil laminate. This will ensure that thethermal transfer printing is correctly positioned within the scannedprint fields over which the thermal transfer printing has been delegatedsuch that, upon a subsequent severing of the web constituted of the foillaminate into predetermined segments forming lid portions for containersor blister packages, the printed information provided thereon withregard to the product will always be correctly located on the finishedpackage.

Furthermore, the invention is also directed to the provision of amulti-layered foil laminate including an outer plastic film materiallayer, which is printed on both surfaces thereof in a manner so as toprovide on one side of the plastic film layer facing the underlying foilmaterial, permanent colored indicia and legends. To the contrary, theprinting which is subsequently imparted on the outer surface of theplastic film material layer of the laminate, and which is appliedthereto through the intermediary of thermal transfer printing, ispositioned in precise registry with the underlying printing previouslyimparted to the opposite or inwardly facing surface of the outer layer.

Accordingly, it is an object of the present invention to provide a noveland inventive method of double-sided printing or; in essence, printingon opposite surfaces of a layer of a multi-layered foil laminate.

It is a more specific object of the present invention to provide amethod of printing as described herein, in which the double-sidedprinting is implemented in that initially one side of the outer, plasticfilm material, which may be transparent or translucent, facing anunderlying metallic foil and adapted to be adhesively secured or bondedthereto is suitably printed in color halftones to provide permanentindicia and coloring background subsequent to lamination of the plasticand metallic layers. The external or opposite surface of the plasticfilm layer is subsequently imprinted through the intermediary of thermaltransfer printing in predetermined registration with the underlyingprinting on the opposite surface of the plastic film layer.

Yet another object of the present invention is to provide amulti-layered foil laminate having at least one outer layer thereofprovided with printing on both sides thereof utilizing the printingmethod pursuant to the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

Reference may now be had to the following detailed description of anembodiment of the invention, taken in conjunction with the accompanyingdrawings; in which:

FIG. 1 illustrates an elevational side view of an apparatus forimplementing the double-sided printing of a layer of a foil laminate,including various workstations for forming a plurality of lid closuresfor packages from a web of the imprinted foil laminate;

FIG. 2 illustrates a top plan view of the apparatus of FIG. 1;

FIG. 3 illustrates, on an enlarged scale, a sensor arrangement utilizedin conjunction with the operation of a printing head for implementingthe double-sided printing of the foil laminate;

FIG. 4 illustrates a fragmentary portion of the foil laminate web whichis adapted for the double-sided printing thereof; and

FIG. 5 illustrates, on an enlarged scale, a sectional view through thefoil laminate taken along line 5--5 in FIG. 4.

DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT

Referring now in detail to the drawings, and specifically to FIGS. 1 and2, there is disclosed an apparatus 10 for the processing of a continuousweb consisting of a multi-layered foil laminate into a plurality of lidor closure structures for plastic containers of the so-called "blisterpackage" type. These containers may be shaped injection-molded plasticstructures of generally rigid or semi-rigid configurations, normallyincorporating product-receiving cavities or compartments, and flangesurfaces to which the lids constituted from portions of the laminate areadapted to be secured or bonded, such as by heat sealing or the like.The apparatus 10 generally includes a plurality of upright frame members12, 14 and 16 rigidly interconnected with horizontal support beams 18and 20 so as to constitute a fixed and stationary support frameworkadapted to be mounted on legs 22 resting on a suitable floor surface.

On a cantilevered extension 24 of a horizontal beam 26, there isjournaled a rotatable structure 28 supporting a roll formed from acontinuous web of a multi-layered foil laminate 30, as described indetail hereinbelow with regard to FIGS. 4 and 5 of the drawings.

Arranged along the longitudinal path of transport of the foil laminate30 along the framework is a housing 32 supporting therein a printinghead arrangement 34 and an optical sensor unit 36.

Furthermore, arranged along the horizontal extent of the framework inthe direction downstream of the printing head arrangement 34 is asuitable slitting unit 40 and various operative devices 42 for severingthe web of foil laminate 30 into suitable lids or covers for containersor packages. These particular workstations and operative components aredescribed in further extensive detail in various copending patentapplications with regard to the formation of the covers or lids from thefoil laminate 30, and consequently are not described in more specificdetail herein.

The foil laminate web 30 is unwound by being drawn by a suitable drivingdevice (not shown) from its rotatable support 28, and guided over aplurality of guide and tension roller units 46 through 48, 50 and 52towards closely and below the printing head arrangement 34 along thehorizontal extent of the apparatus 10.

The multi-layered foil laminate 30 is constituted of a plurality oflayers of various materials which are adhesively secured or bonded toeach other, as shown in detail in FIGS. 4 and 5 of the drawings.

Reverting to FIG. 5, the multi-layered foil laminate 30 includes anupper layer 50 constituted of a substantially transparent or translucentpolyester film material which has been previously imprinted viaconventional lithography on its lower surface 52 with suitable indiciawhich may be in solid or colored halftones, including reversely printedlegends as required, and which may also include a further color or printlayer therebeneath forming a colorated or contrasting background, forinstance, such as white or any other suitable color. Inasmuch as theindicia of halftones and the background beneath the polyester film web50 are printed on interior surface 52, upon viewing from the outsidetowards the outer surface of the polyester film web 50, as shown in FIG.4 of the drawings, in view of the transparency of the polyester film,the various indicia and legends which may be representative of thecompany name, logo, various decorative and advertising matters andprinted information which is to be permanently provided for products ofthis type in general. While conventional lithography is used in thepreferred embodiment, it should be noted that other forms of printingprocesses could be utilized. Suitable print fields 52a, 52b and 52c maybe clearly ascertained and viewed from the exterior of the film layer50. A foil web 54 consisting preferably of aluminum extends adjacent thelower surface 52 of the polyester film and is adhesively secured orbonded thereto through the interposition of an adhesive layerconstituted of a dry bonding adhesive 56, which may be polyurethane.

The other side or surface of the aluminum foil web 54 may also be coatedwith a further adhesive layer 58 similar to that of adhesive layer 56,and which is also constituted of polyurethane. This adhesive is intendedto provide an adhesive connection or bond between the lower surface ofthe aluminum foil web 54 and a further plastic film layer 60 which maybe constituted of polypropylene, and which provides for a good sealingadherence to the plastic material of an injection-molded plastic packageor container; for instance, through heat sealing thereto or the like.Suitable plastic films other than polyester and which are substantiallytransparent, which may be imprinted on both sides thereof may include,among others, low and medium density polyethylenes, EVA copolymers,ionomers, cellulosic materials and the like.

Prior to the forming of the adhesive bond between the upper polyesterfilm layer 50 and the adhesive 52 in order to laminate the layer 50 tothe aluminum foil web 54, suitable imprinting is implemented. Thisprinting as mentioned hereinbefore, is imparted to the lower surface 52of the polyester film 50 in that indicia and legends, as mentionedhereinbefore, are applied through halftone color printing in suitableorientation such that upon adhesive securing or bonding thereof to thealuminum foil 54, the indicia will be viewable through the layer 50 fromthe top of the laminate 30 in the correctly represented orientationthereof, as may be the case in the above-mentioned U.S. Pat. No.4,691,820.

As the laminated foil web 30 is advanced guided over the series ofrollers 46 through 52 towards the printing head arrangement 34, theoptical sensor unit 36 is adapted to scan and determine the location ofat least one of the print fields 52a or 52b or 52c printed on the lowersurface 52, so as to cause the printing head arrangement 34 to advance aceramic printing head 34a into contact with the applicable printingfields 52a through 52c, and through the intermediary of thermal transferprinting, imprint appropriately variable and changeable printed data isimparted to the exterior surface of the polyester film 50. Such data;for example, when the laminate is severed into lid-forming labels forrespective packages, may consist of suitable changeable lot numbers,expiration dates, and other physical data representative of the specificproduct housed in the package; for instance, data with regard to thepower of a contact lens which is stored within a cavity of the packagewhile immersed in a suitable protective sterilized saline solution.

Thus, the initial printing of the permanent indicia and legends whichare provided on the lower surface 52 of the polyester film 50, whichsurface is adhesively bonded to the aluminum foil web 54, serves as apermanent display of the various generalized product-identifying andcompany-related information, advertising and logos or the like, whileconcurrently having at least one of the print fields serving as aregister for imprinting by means of thermal transfer printing, otherspecific and variable product-related data onto the external surface ofthe foil laminate 30.

The foregoing thermal transfer printing is adapted to withstandtemperatures in excess of 120° C. for periods of up to one-half hour,which temperatures may be encountered when the finished package and theproduct contained therein are subjected to sterilization under thoseconditions, without in any manner adversely affecting the quality andreadability of the thermal transfer printing on the outer layer of thefoil laminate 30. It is preferable to attain stable indicia by thermaltransfer printing which indicia can withstand temperatures in the rangeof 1207 C. to 1307 C. over periods of about 30 minutes.

The foil laminate 30 may have its overall thickness within a range ofapproximately 0.07 to 0.08 mm, and may be supplied in suitable rolls ofweb lengths and sizes commensurate with the particular intendedapplications for the foil laminate.

From the foregoing, it becomes readily apparent to one of skill in theart that the utilization of the double-sided printing of the outerpolyester film layer of the laminate provides advantages not attainablein the art, inasmuch as there is avoided the need for registrationapertures and marks in the laminate, there is no necessity for employinglaser printing, the latter of which does not always provide theappropriate printing quality, the elimination of the need for heat-stampprinting, which causes the forming of indentation in the foil laminate,thereby adversely affecting the proper heat sealing thereof with aplastic package containing the product. The present invention, incontrast therewith, provides a satisfactory printing on the externalsurface of laminate which is severed to form labels for the packages,which printing is resistant to abrasion and to obliteration caused byhigh temperatures being present over extensive periods of time, andwhich also provides for an adequate storage shelf-life for the completedpackage.

While there has been shown and described what is considered to be apreferred embodiment of the invention, it will, of course, be understoodthat various modifications and changes in form or detail could readilybe made without departing from the spirit of the invention. It is,therefore, intended that the invention be not limited to the exact formthan the whole of the invention herein disclosed as hereinafter claimed.

What is claimed is:
 1. A method of printing on opposite surfaces of alayer from a multi-layered foil laminate, wherein said layer comprises aplastic film material, comprising either translucent or transparentmaterial, having a first surface adhesively fastenable to a facingsurface of a foil web; said method comprising the steps of:(a)imprinting a first indicia on said first surface of said plastic filmmaterial through lithographic printing; (b) adhesively fastening saidimprinted first surface of said plastic film material layer to thefacing surface of said foil web; and (c) imprinting second indicia on asecond surface of said plastic film material remote from said foil webthrough thermal transfer printing; wherein said first indicia assistsprinting registration for determining the location of the secondindicia.
 2. A method of printing as claimed in claim 1, wherein saidplastic film material is at least translucent, said lithographicprinting step comprising printing said first indicia in at least onecolor on said first surface so as to render said first indicia visiblein a desired orientation thereof upon viewing said second surface fromthe exterior of said laminate.
 3. A method of printing as claimed inclaim 2, wherein an opaque contrastingly colored background is printedon said first surface beneath said first indicia.
 4. A method ofprinting as claimed in claim 1, wherein said thermal transfer printingstep on said second surface of the plastic film material has the secondindicia remaining stable upon being exposed to temperatures within therange of about 120° C. to 130° C. over periods of about 30 minutes.
 5. Amethod of printing as claimed in claim 1, wherein said plastic filmmaterial layer is constituted of polyester.
 6. A method of printing asclaimed in claim 5, wherein said foil web is constituted of aluminum. 7.A method of printing as claimed in claim 1, wherein said plastic filmmaterial is adhesively secured to said foil web through theinterposition of a layer consisting of a dry bond adhesive.
 8. A methodof printing as claimed in claim 7, wherein said dry bond adhesivecomprises a polyurethane adhesive.
 9. A method of printing as claimed inclaim 1, wherein a surface of said foil web opposite the surface towhich said plastic film material is adhered has applied thereto insuperposition:(a) a layer of a dry bond adhesive coated on said foilweb; and (b) a further layer comprising a plastic film materialpositioned on said dry bond adhesive.
 10. A method of printing asclaimed in claim 9, wherein said dry bond adhesive comprises apolyurethane adhesive.
 11. A method of printing as claimed in claim 9,wherein said further plastic film material is constituted of orientedpolypropylene.
 12. A method of printing as claimed in claim 1, whereinsaid thermal transfer printing step is implemented by a ceramic printhead contacting the second surface of said plastic film material.
 13. Amethod of printing as claimed in claim 12, wherein the second surface ofsaid plastic film material is an outer exposed surface of said foillaminate enabling external viewing of the indicia printed on bothsurfaces thereof.
 14. A method of printing as claimed in claim 1,wherein said printing registration is controlled by at lest one opticalsensor scanning at least one print field of said first indicia.
 15. Amethod of printing as claimed in claim 13, wherein said second indiciaimparted by thermal transfer printing to the second surface of saidplastic film material are located in specified orientations over printfields present on the first surface of said plastic film material.
 16. Amethod of printing as claimed in claim 9, wherein said foil laminate hasan overall thickness of about 0.07 to 0.08 mm.